Modified polyurethane dispersion and preparation method thereof

Abstract

The invention relates to a modified polyurethane dispersion and a preparation method thereof. The modified waterborne polyurethane dispersion is prepared from the following raw materials: polyisocyanate, macromolecular polyol, silanediol, a hydrophilic chain extender and a modified monomer. A printing coating prepared from the modified polyurethane dispersion has excellent moisture permeability and washing resistance on silicone oil treated cloth.

Description

Technical Field

[0001] The invention relates to the field of polyurethane dispersions, in particular to a modified polyurethane dispersion which can achieve moisture permeability on silicone oil treated cloth without affecting adhesion and water-based properties, and a preparation method thereof. Background Art

[0002] Waterborne polyurethane dispersion can form a dense and transparent film on the surface of fabrics. This film has good adhesion and elasticity, so it is often used on the surface of fabrics. Printing with waterborne polyurethane dispersion only requires drying without washing. The operation process is simple, and the discharge of solvents and sewage can be reduced. It meets environmental protection requirements and is one of the commonly used methods in the printing field.

[0003] As people's living standards improve, their requirements for clothing and shoes are getting higher and higher. Therefore, the color fastness or washing fastness of printing on clothing and shoes has become one of the concerns. The existing substrates used for printing are generally cotton cloth, cotton elastic cloth, and more and more substrates treated with heavy silicone oil on the market. The fastness of ordinary water-based resins on these substrates will be relatively poor.

[0004] At present, most of the clothes printed with glue on the market are not breathable, especially wearing T-shirts with large-area prints in the summer, which is very stuffy. Therefore, it is very important to invent a print that can discharge sweat vapor in time when the human body sweats and increase comfort.

[0005] With the development of waterborne polyurethane technology, hydrophilic group penetration technology has been increasingly studied in the field of waterproof and breathable properties. Patent CN114437307A waterborne polyurethane dispersion, coating composition and its application, by introducing a diol containing a polyethylene oxide group in the side chain to enhance the breathable properties, but this group leads to a decrease in water washing resistance while improving the breathable properties.

[0006] How to ensure the washability and adhesion of polyurethane printing while still having good perspective has become the focus of research in the industry. Summary of the invention

[0007] In view of the above problems, the present invention provides a modified aqueous polyurethane dispersion and a preparation method thereof, wherein the printed product prepared therefrom has excellent moisture permeability, and has excellent adhesion and water washability on silicone oil treated cloth.

[0008] To achieve the above objectives, the present invention adopts the following technical solutions:

[0009] A modified polyurethane dispersion comprising the following raw materials in percentage by weight:

[0010] Component 1) polyisocyanate 30-50wt%, preferably 32-44wt%;

[0011] Component 2) 40-60 wt % of macromolecular polyol, preferably 45-58 wt %;

[0012] Component 3) 1-6 wt% of silicon glycol;

[0013] Component 4) hydrophilic chain extender 4-6wt%;

[0014] The sum of the total mass of components 1)-4) is 100%;

[0015] In the present invention, the raw materials further include: component 5) a polyamine chain extender in an amount of 3-6 wt% of the total mass of component 1) to component 4);

[0016] In the present invention, the raw materials further include: component 6) modified monomer, the amount of which is 125-140% of the total mass of component 1)-component 4);

[0017] The modified monomers include hard monomers containing double bonds, soft monomers containing double bonds, and sulfonate monomers containing double bonds; preferably, the amount of the hard monomers containing double bonds in the modified monomers is 15-30wt% of the mass of the modified monomers; the amount of the soft monomers containing double bonds is 55-75wt% of the mass of the modified monomers; and the amount of the sulfonate monomers containing double bonds is 7-17wt% of the mass of the modified monomers;

[0018] The raw materials also include: component 7) an initiator, the amount of which is 0.05-0.3% of the total mass of the modified monomer, preferably 0.1-0.2%;

[0019] In the present invention, the raw materials also include: component 8) catalyst, the amount of which is 0.01-1% of the total mass of component 1) to component 4).

[0020] In the present invention, the polyisocyanate is selected from aliphatic polyisocyanates, alicyclic polyisocyanates, aromatic polyisocyanates or mixtures thereof, including but not limited to toluene diisocyanate, diphenylmethane diisocyanate, trimethylhexane diisocyanate, hexahydrotoluene diisocyanate, 1,4-cyclohexane diisocyanate, dodecyl diisocyanate and dicyclohexylmethane diisocyanate, etc. One or more, preferably one or more of HDI, IPDI and HMDI.

[0021] In the present invention, the molecular weight of the macromolecular polyol is 1000-2000, and is preferably selected from one or a combination of polyether polyols, such as PTMG, PPG, and the like.

[0022] In the present invention, the silicon diol is selected from diphenyl silicon diol.

[0023] In the present invention, the hydrophilic chain extender is selected from one or more of dimethylol propionic acid, dimethylol butyric acid, diaminobenzoic acid, sodium dihydroxypropane sulfonate, amino acids, and aminosulfonates.

[0024] In the present invention, the polyamine chain extender is an organic or inorganic primary or secondary amine functional compound containing at least two active hydrogen atoms, preferably including one or more of ethylenediamine, isophoronediamine, hexamethylenediamine, diethylenetriamine, phenylenediamine, toluenediamine, and dicyclohexylmethanediamine.

[0025] In the present invention, the hard monomer containing a double bond is selected from one or more of methyl methacrylate, styrene, α-methylstyrene, α-methylstyrene, p-methylstyrene or vinyltoluene;

[0026] In the present invention, the soft monomer containing a double bond is selected from one or more of ethyl acrylate, n-butyl acrylate, 2-ethylheptyl acrylate, isooctyl acrylate, isobutyl acrylate, cyclohexyl acrylate, 2-ethylhexyl acrylate, vinyl acetate and vinyl propionate;

[0027] In the present invention, the sulfonate containing a double bond is selected from one or more of sodium propylene sulfonate and sodium methpropylene sulfonate.

[0028] In the present invention, the initiator initiation system is a redox system;

[0029] Preferably, the oxidant includes one or more of ammonium persulfate, sodium persulfate, potassium persulfate, di-tert-butyl peroxide, hydrogen peroxide, cumene hydroperoxide and tert-butyl hydroperoxide, and tert-butyl hydroperoxide is further preferred;

[0030] Preferably, the reducing agent includes one or more of ferrous sulfate, silver nitrate, mercaptan, ferrous chloride, sodium pyrosulfite, sodium bisulfite and isoascorbic acid, and sodium pyrosulfite is more preferred.

[0031] In the present invention, the modified polyurethane dispersion synthesis method is as follows:

[0032] a. Add polyisocyanate, macromolecular polyol, silicon diol, hydrophilic chain extender, catalyst and solvent into the reaction kettle and mix them evenly, and react at 50-80°C until the theoretical NCO value is reached to obtain a prepolymer;

[0033] b. Cool the system to 50-60°C, add the solvent and a portion of the modified monomer, stir and mix, and continue to cool to 27-35°C;

[0034] c. Add water to the cooled system for dispersion treatment;

[0035] d. After the dispersion is completed, the polyamine chain extender is added to the system to obtain a modified aqueous polyurethane dispersion emulsion;

[0036] e. Add the remaining modified monomer to the modified aqueous polyurethane dispersion emulsion for swelling, add an initiator for free radical polymerization, remove the solvent after the polymerization is completed, and obtain a modified polyurethane dispersion.

[0037] Preferably, the mass of the modified monomer initially added in step b is 50-75%, preferably 55-70%, of the total amount of the modified monomer.

[0038] Preferably, the stirring and mixing time in step b is 2-10 min.

[0039] The modified polyurethane dispersion of the invention has a solid content of 50-55%, a particle size of 120-150 nm, and obvious blue light.

[0040] According to the preparation method of the present invention, in some embodiments, the catalyst is selected from an organic bismuth catalyst, for example, a bismuth isooctanoate catalyst, a bismuth laurate catalyst, a bismuth neodecanoate catalyst, and is preferably selected from the organic bismuth Coscat83.

[0041] In the present invention, the modified aqueous polyurethane dispersion prepared by the above method can be used in the field of clothing that has high requirements on moisture permeability, adhesion and water washability.

[0042] The positive effects of the present invention are mainly reflected in the following aspects:

[0043] The modified waterborne polyurethane composition is prepared to form a core-shell structure, which is more conducive to the entanglement between the molecular chains of the two than the simple blending of polyurethane emulsion and polyacrylate emulsion, improves the polymerization stability, and complements each other's advantages; the introduction of sulfonate monomers, whose strong hydrophilicity can be used as a water vapor permeation channel, enhances the moisture permeability of the printing; the introduction of silicon diol monomers can increase the combination with silicone oil-treated cloth, thereby increasing the adhesion and water washability of the printing on the silicone oil-treated cloth. DETAILED DESCRIPTION

[0044] The testing method in the present invention is as follows:

[0045] Moisture permeability test: According to the ASTM E-96 1995BW standard test method, the moisture permeability of the waterproof and breathable products of the embodiments and comparative examples was tested.

[0046] Washing resistance test: According to the AATCC 135-2004 (W0&W5) standard test method, the printed products prepared in each embodiment and comparative example were washed with 40°C water and laundry detergent. After washing for 5 times, the moisture permeability and surface damage degree of the printed products were measured again by the above method.

[0047] The construction process of preparing printed products with dispersion is as follows: according to the formula shown in the table below, the water-based polyurethane dispersion resin and the auxiliary agent system are coated on the heavy silicone oil treated cloth by hand screen printing, screen printing or rotary screen printing, two times and four knives. The prepared sample is placed in a 50℃ oven for curing for 24 hours, and then continued to be balanced and dried in a constant temperature and humidity room (temperature: 25℃, humidity: 65% rh) for 48 hours before being tested as a test sample.

[0048] The construction formula of printed products is as follows:

[0049]

[0050]

[0051] The raw materials used in the examples are as follows:

[0052] (dicyclohexylmethane diisocyanate, NCO% content is about 32.0%, Wanhua Chemical Group Co., Ltd.);

[0053] (isophorone diisocyanate, NCO% content is about 37.8%, Wanhua Chemical Group Co., Ltd.);

[0054] PPG2000 (polypropylene glycol, hydroxyl value 56 mgKOH / g, number average molecular weight ≈ 2000, functionality 2, Dongda Chemical);

[0055] PTMG2000 (polytetramethylene glycol, hydroxyl value 56 mgKOH / g, number average molecular weight 2000, functionality 2, Yantai Huada Chemical);

[0056] PTMG1000 (polytetramethylene glycol, hydroxyl value 112 mgKOH / g, number average molecular weight 1000, functionality 2, Yantai Huada Chemical);

[0057] Diphenylsilanediol, Hubei Jiufenglong Chemical Co., Ltd.

[0058] Styrene, Wanhua Chemical Group Co., Ltd.;

[0059] Methyl methacrylate, Tianjin Kemeiou Chemical Reagent Co., Ltd.;

[0060] n-Butyl acrylate, Wanhua Chemical Group Co., Ltd.;

[0061] Ethyl acrylate, Tianjin Kemeiou Chemical Reagent Co., Ltd.;

[0062] Isooctyl acrylate, Tianjin Kemeiou Chemical Reagent Co., Ltd.;

[0063] Sodium metabisulfite (Xilong Chemical Co., Ltd.)

[0064] TBHP (tert-butyl hydroperoxide, Xilong Chemical Co., Ltd.)

[0065] Sodium propylene sulfonate, Shandong Yousuo Chemical Technology Co., Ltd.

[0066] Sodium Methylpropene Sulfonate, Hubei Qiniu Chemical Technology Co., Ltd.

[0067] Example 1

[0068] Into a four-necked flask equipped with a reflux condenser, a thermometer and a mechanical stirrer, 32 g of IPDI, 58 g of PTMG2000, 3 g of diphenylsilanediol, 4 g of dimethylolpropionic acid, 0.3 g of organic bismuth Coscat83 and 40 g of acetone were added and mixed evenly, and reacted at 80° C. until the theoretical NCO value reached, to obtain a prepolymer;

[0069] The system was cooled to 60°C, 100 g of acetone, 12.6 g of styrene monomer, 63 g of n-butyl acrylate monomer, and 8.4 g of sodium propylene sulfonate were added and stirred for 5 min, and the temperature was further cooled to 30-35°C;

[0070] 186.2 g of deionized water was added to the cooled system and dispersed under high-speed shearing conditions;

[0071] Slowly add 3 g of ethylenediamine diluted with 40 g of water into the system to obtain a modified waterborne polyurethane dispersion emulsion;

[0072] A pre-emulsion consisting of 6.3 g of styrene monomer, 31.5 g of n-butyl acrylate monomer and 4.2 g of sodium acrylic acid sulfonate was added to the system, the temperature was raised to 35°C and stirred for 1 hour, 0.063 g of tert-butyl hydroperoxide and 0.063 g of sodium metabisulfite were added in sequence to initiate free radical polymerization. After the polymerization was completed, the acetone in the emulsion was removed by reduced pressure distillation to obtain a modified waterborne polyurethane dispersion with a particle size of 120 nm and obvious blue light.

[0073] Example 2

[0074] Into a four-necked flask equipped with a reflux condenser, a thermometer and a mechanical stirrer, 39 g of HMDI, 45 g of PTMG1000, 6 g of diphenylsilanediol, 6 g of dihydroxymethylbutyric acid, 0.3 g of organic bismuth Coscat83 and 40 g of acetone were added and mixed evenly, and reacted at 80° C. until the theoretical NCO value was reached to obtain a prepolymer;

[0075] The system was cooled to 60°C, 100 g of acetone, 26.88 g of methyl methacrylate monomer, 49.28 g of n-butyl acrylate monomer, and 13.44 g of sodium propylene sulfonate were added and stirred for 5 min, and the temperature was further cooled to 30-35°C;

[0076] 152 g of deionized water was added to the cooled system and dispersed under high-speed shearing conditions;

[0077] Slowly adding 4 g of isophorone diamine diluted with 40 g of water into the system to obtain a modified waterborne polyurethane dispersion emulsion;

[0078] A pre-emulsion consisting of 13.44 g of methyl methacrylate monomer, 24.64 g of n-butyl acrylate monomer and 6.72 g of sodium propylene sulfonate was added to the system, the temperature was raised to 35°C and stirred for 1 hour, 0.135 g of tert-butyl hydroperoxide and 0.135 g of sodium metabisulfite were added in sequence to initiate free radical polymerization. After the polymerization was completed, the acetone in the emulsion was removed by reduced pressure distillation to obtain a modified waterborne polyurethane dispersion with a particle size of 132 nm and obvious blue light.

[0079] Example 3

[0080] Into a four-necked flask equipped with a reflux condenser, a thermometer and a mechanical stirrer, 11 g IPDI, 33 g HMDI, 48 g PTMG 1000, 1 g diphenylsilanediol, 4 g dimethylolpropionic acid, 0.3 g organic bismuth Coscat83 and 40 g acetone were added and mixed evenly, and reacted at 80° C. until the theoretical NCO value was reached to obtain a prepolymer;

[0081] The system was cooled to 60°C, 100 g of acetone, 19.2 g of methyl methacrylate monomer, 56.7 g of isooctyl acrylate monomer, and 11.3 g of sodium methyl propylene sulfonate were added and stirred for 5 min, and the temperature was further cooled to 30-35°C;

[0082] 173.4 g of deionized water was added to the cooled system and dispersed under high-speed shearing conditions;

[0083] 3g of ethylenediamine diluted with 40g of water was slowly added into the system to obtain a modified aqueous polyurethane dispersion emulsion.

[0084] A pre-emulsion consisting of 9.6 g of methyl methacrylate monomer, 28 g of isooctyl acrylate monomer, and 5.7 g of sodium methyl propylene sulfonate was added to the system, the temperature was raised to 35°C and stirred for 1 hour, 0.098 g of tert-butyl hydroperoxide and 0.098 g of sodium metabisulfite were added in sequence to initiate free radical polymerization. After the polymerization was completed, the acetone in the emulsion was removed by reduced pressure distillation to obtain a modified waterborne polyurethane dispersion with a particle size of 148 nm and obvious blue light.

[0085] Example 4

[0086] 23 g HMDI, 12 g HDI, 51 g PTMG 1000, 3 g diphenylsilanediol, 5 g dihydroxymethylbutyric acid, 0.3 g organic bismuth Coscat83 and 40 g acetone were added into a four-necked flask equipped with a reflux condenser, a thermometer and a mechanical stirrer, mixed evenly, and reacted at 80° C. until the theoretical NCO value reached, to obtain a prepolymer;

[0087] The system was cooled to 60°C, 100 g of acetone, 26.32 g of styrene monomer, 55.3 g of n-butyl acrylate monomer, and 6.13 g of sodium methyl propylene sulfonate monomer were added and stirred for 5 min, and the temperature was further cooled to 30-35°C;

[0088] 191.7 g of deionized water was added to the cooled system and dispersed under high-speed shearing conditions;

[0089] Slowly add 6 g of isophorone diamine diluted with 40 g of water into the system to obtain a modified waterborne polyurethane dispersion emulsion;

[0090] A pre-emulsion consisting of 13.16 g of styrene monomer, 27.6 g of n-butyl acrylate monomer and 3 g of sodium methyl acrylate sulfonate monomer was added to the system, the temperature was raised to 35°C and stirred for 1 hour, 0.07 g of tert-butyl hydroperoxide and 0.07 g of sodium metabisulfite were added in sequence to initiate free radical polymerization. After the polymerization was completed, the acetone in the emulsion was removed by reduced pressure distillation to obtain a modified waterborne polyurethane dispersion with a particle size of 120 nm and obvious blue light.

[0091] Example 5

[0092] Into a four-necked flask equipped with a reflux condenser, a thermometer and a mechanical stirrer, 10 g HDI, 25 g IPDI, 51 g PTMG 1000, 3 g diphenylsilanediol, 5 g dihydroxymethylbutyric acid, 0.3 g organic bismuth Coscat83 and 40 g acetone were added and mixed evenly, and reacted at 80° C. until the theoretical NCO value reached, to obtain a prepolymer;

[0093] The system was cooled to 60°C, 100 g of acetone, 19.6 g of styrene monomer, 51.1 g of n-butyl acrylate monomer, and 14.5 g of sodium propylene sulfonate were added and stirred for 5 min, and the temperature was further cooled to 30-35°C;

[0094] 188 g of deionized water was added to the cooled system and dispersed under high-speed shearing conditions;

[0095] Slowly add 6 g of isophorone diamine diluted with 40 g of water into the system to obtain a modified waterborne polyurethane dispersion emulsion;

[0096] A pre-emulsion consisting of 9.8 g of styrene monomer, 25.6 g of n-butyl acrylate monomer and 7.2 g of sodium propylene sulfonate was added to the system, the temperature was raised to 35°C and stirred for 1 hour, 0.096 g of tert-butyl hydroperoxide and 0.096 g of sodium metabisulfite were added in sequence to initiate free radical polymerization. After the polymerization was completed, the acetone in the emulsion was removed by reduced pressure distillation to obtain a modified waterborne polyurethane dispersion with a particle size of 125 nm and obvious blue light.

[0097] Comparative Example 1

[0098] Into a four-necked flask equipped with a reflux condenser, a thermometer and a mechanical stirrer, 11 g IPDI, 33 g HMDI, 48 g PTMG 1000, 5 g dimethylol propionic acid, 0.3 g organic bismuth Coscat83 and 40 g acetone were added and mixed uniformly, and reacted at 80° C. until the theoretical NCO value was reached to obtain a prepolymer;

[0099] The system was cooled to 60°C, 100 g of acetone, 19.2 g of methyl methacrylate monomer, 56.7 g of isooctyl acrylate monomer, and 11.3 g of sodium methyl propylene sulfonate were added and stirred for 5 min, and the temperature was further cooled to 30-35°C;

[0100] 173.4 g of deionized water was added to the cooled system and dispersed under high-speed shearing conditions;

[0101] 3g of ethylenediamine diluted with 40g of water was slowly added into the system to obtain a modified aqueous polyurethane dispersion emulsion.

[0102] A pre-emulsion consisting of 9.6 g of methyl methacrylate monomer, 28 g of isooctyl acrylate monomer, and 5.7 g of sodium methyl propylene sulfonate was added to the system, the temperature was raised to 35°C and stirred for 1 hour, 0.098 g of tert-butyl hydroperoxide and 0.098 g of sodium metabisulfite were added in sequence to initiate free radical polymerization. After the polymerization was completed, the acetone in the emulsion was removed by reduced pressure distillation to obtain a modified waterborne polyurethane dispersion with a particle size of 150 nm and obvious blue light.

[0103] Comparative Example 2

[0104] 23 g HMDI, 12 g HDI, 51 g PTMG 1000, 3 g diphenylsilanediol, 5 g dihydroxymethylbutyric acid, 0.3 g organic bismuth Coscat83 and 40 g acetone were added into a four-necked flask equipped with a reflux condenser, a thermometer and a mechanical stirrer, mixed evenly, and reacted at 80° C. until the theoretical NCO value reached, to obtain a prepolymer;

[0105] The system was cooled to 60°C, 100 g of acetone, 26.32 g of styrene monomer, and 61.4 g of n-butyl acrylate monomer were added and stirred for 5 min, and the temperature was further cooled to 30-35°C;

[0106] 165 g of deionized water was added to the cooled system and dispersed under high-speed shearing conditions;

[0107] Slowly add 6 g of isophorone diamine diluted with 40 g of water into the system to obtain a modified waterborne polyurethane dispersion emulsion;

[0108] A pre-emulsion consisting of 13.16 g of styrene monomer and 30.7 g of n-butyl acrylate monomer was added to the system, the temperature was raised to 35°C and stirred for 1 hour, 0.07 g of tert-butyl hydroperoxide and 0.07 g of sodium metabisulfite were added in sequence to initiate free radical polymerization. After the polymerization was completed, the acetone in the emulsion was removed by reduced pressure distillation to obtain a modified waterborne polyurethane dispersion with a particle size of 134 nm and obvious blue light.

[0109] Comparative Example 3

[0110] Into a four-necked flask equipped with a reflux condenser, a thermometer and a mechanical stirrer, 11 g IPDI, 33 g HMDI, 48 g PTMG 1000, 5 g dimethylol propionic acid, 0.3 g organic bismuth Coscat83 and 40 g acetone were added and mixed uniformly, and reacted at 80° C. until the theoretical NCO value was reached to obtain a prepolymer;

[0111] The system was cooled to 60°C, 100 g of acetone, 26.32 g of methyl methacrylate monomer, and 61.4 g of isooctyl acrylate monomer were added and stirred for 5 min, and the temperature was further cooled to 30-35°C;

[0112] 182.7 g of deionized water was added to the cooled system and dispersed under high-speed shearing conditions;

[0113] 3g of ethylenediamine diluted with 40g of water was slowly added into the system to obtain a modified aqueous polyurethane dispersion emulsion.

[0114] A pre-emulsion consisting of 13.16 g of methyl methacrylate monomer and 30.7 g of isooctyl acrylate monomer was added to the system, the temperature was raised to 35°C and stirred for 1 hour, 0.098 g of tert-butyl hydroperoxide and 0.098 g of sodium metabisulfite were added in sequence to initiate free radical polymerization. After the polymerization was completed, the acetone in the emulsion was removed by reduced pressure distillation to obtain a modified waterborne polyurethane dispersion with a particle size of 146 nm and obvious blue light.

[0115] The compositions prepared in each example and comparative example were used to prepare modified waterborne polyurethane compositions according to the printing formula listed in the specific implementation manner, and performance tests were performed. The performance test results of the obtained printings are shown in the following table:

[0116]

[0117] It can be seen from the above table that the modified polyurethane composition prepared in the present invention can achieve good results in terms of moisture permeability and water washability in printing.

Claims

1. A modified polyurethane dispersion comprising the following raw materials in percentage by weight: Component 1) polyisocyanate 30-50wt%, preferably 32-44wt%; Component 2) 40-60 wt % of macromolecular polyol, preferably 45-58 wt %; Component 3) 1-6 wt% of silicon glycol; Component 4) hydrophilic chain extender 4-6wt%; The total mass of components 1) to 4) is taken as 100%.

2. The modified polyurethane dispersion according to claim 1, characterized in that The raw materials also include: component 5) a polyamine chain extender in an amount of 3-6 wt% of the total mass of component 1) to component 4); Preferably, the raw materials further include: component 6) modified monomer, the amount of which is 125-140% of the total mass of component 1) - component 4).

3. The modified polyurethane dispersion according to claim 1, characterized in that The modified monomers include hard monomers containing double bonds, soft monomers containing double bonds, and sulfonate monomers containing double bonds; preferably, the amount of the hard monomers containing double bonds in the modified monomers is 15-30wt% of the mass of the modified monomers; the amount of the soft monomers containing double bonds is 55-75wt% of the mass of the modified monomers; The amount of the double bond sulfonate monomer used is 7-17 wt % of the mass of the modified monomer.

4. The modified polyurethane dispersion according to any one of claims 1 to 3, characterized in that: The raw materials also include: component 7) an initiator, the amount of which is 0.05-0.3% of the total mass of the modified monomer, preferably 0.1-0.2%; Preferably, the raw material further comprises: component 8) catalyst, the amount of which is 0.01%-1% of the total mass of components 1)-component 4).

5. The modified polyurethane dispersion according to any one of claims 1 to 4, characterized in that: The polyisocyanate is selected from aliphatic polyisocyanates, alicyclic polyisocyanates, aromatic polyisocyanates or mixtures thereof, including but not limited to one or more of toluene diisocyanate, diphenylmethane diisocyanate, trimethylhexane diisocyanate, hexahydrotoluene diisocyanate, 1,4-cyclohexane diisocyanate, dodecyl diisocyanate and dicyclohexylmethane diisocyanate, preferably one or more of HDI, IPDI and HMDI.

6. The modified polyurethane dispersion according to any one of claims 1 to 5, characterized in that: The molecular weight of the macromolecular polyol is 1000-2000, preferably polyether polyol; Preferably, the silicon diol is selected from diphenyl silicon diol; Preferably, the hydrophilic chain extender is selected from one or more of dimethylolpropionic acid, dimethylolbutyric acid, diaminobenzoic acid, sodium dihydroxypropanesulfonate, amino acids, and aminosulfonates; Preferably, the polyamine chain extender is an organic or inorganic primary or secondary amine functional compound containing at least two active hydrogen atoms, preferably including one or more of ethylenediamine, isophoronediamine, hexamethylenediamine, diethylenetriamine, phenylenediamine, toluenediamine, and dicyclohexylmethanediamine.

7. The modified polyurethane dispersion according to any one of claims 1 to 6, characterized in that: The hard monomer containing a double bond is selected from one or more of methyl methacrylate, styrene, α-methylstyrene, α-methylstyrene, p-methylstyrene or vinyltoluene; Preferably, the soft monomer containing a double bond is selected from one or more of ethyl acrylate, n-butyl acrylate, 2-ethylheptyl acrylate, isooctyl acrylate, isobutyl acrylate, cyclohexyl acrylate, 2-ethylhexyl acrylate, vinyl acetate and vinyl propionate; Preferably, the sulfonate containing a double bond is selected from one or more of sodium propylene sulfonate and sodium methyl propylene sulfonate; Preferably, the catalyst is selected from an organic bismuth catalyst; Preferably, the initiator initiation system is a redox system; Preferably, the oxidant comprises one or more of ammonium persulfate, sodium persulfate, potassium persulfate, di-tert-butyl peroxide, hydrogen peroxide, cumene hydroperoxide and tert-butyl hydroperoxide, and tert-butyl hydroperoxide is further preferred; Preferably, the reducing agent includes one or more of ferrous sulfate, silver nitrate, mercaptan, ferrous chloride, sodium pyrosulfite, sodium bisulfite and isoascorbic acid, and sodium pyrosulfite is more preferred.

8. The method for preparing a modified polyurethane dispersion according to any one of claims 1 to 7, characterized in that: The following steps are involved: a. Add polyisocyanate, macromolecular polyol, silicon diol, hydrophilic chain extender, catalyst and solvent into the reaction kettle and mix them evenly, and react at 50-80°C until the theoretical NCO value is reached to obtain a prepolymer; b. Cool the system to 50-60°C, add the solvent and a portion of the modified monomer, stir and mix, and continue to cool to 27-35°C; c. Add water to the cooled system for dispersion treatment; d. After the dispersion is completed, the polyamine chain extender is added to the system to obtain a modified aqueous polyurethane dispersion emulsion; e. Add the remaining modified monomer to the modified aqueous polyurethane dispersion emulsion for swelling, add an initiator for free radical polymerization, remove the solvent after the polymerization is completed, and obtain a modified polyurethane dispersion.

9. The method for preparing a modified polyurethane dispersion according to claim 8, characterized in that: The mass of the modified monomer first added in step b is 50-75% of the total amount of the modified monomer, preferably 55-70%; Preferably, the stirring and mixing time in step b is 2-10 min.

10. A modified polyurethane dispersion according to any one of claims 1 to 7 or a modified polyurethane dispersion prepared by the preparation method according to claim 8 or 9, which is used in the field of clothing.

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